WikiLeaks protesters had vowed to march through Sydney despite being refused permission by police.

Assistant Commissioner and Commander of the Central Metropolitan Region Mark Murdoch wrote a letter to the Support WikiLeaks Coalition, the organisers of the protest, denying them permission to hold their event.

It appears that the police would rather be minding Oprah than looking after the legitimate rights of the public to freedom of expression

He said the refusal was based on the fact that the group did not provide seven days' notice of their planned protest.

"This is a requirement for all groups requesting permission to protest.

"This group gave one day's notice of their desire to march along George Street from Town Hall to Martin Place in peak hour; this would cause too much disruption and was not acceptable," Assistant Commissioner Murdoch said.

In the letter, he warned the group they did not "have the protection for obstruction type offences".

"However, NSW Police offered to facilitate a static protest, an alternate route, and also offered to facilitate a march along George Street at another time.

"Furthermore, a similar protest last Friday at Town Hall was assisted by police despite the Form 1 application again not complying with requirements.

"Police explained the requirements then to the organisers so they were well aware of what was needed.

"These are requirements for every group requesting permission to march," Assistant Commissioner Murdoch said.